Gearhead



Dec. 5, 1961 M. B. MOORE 3,011,358

. GEARHEAD Filed Sept. 6, 1960 3 Sheets-Sheet 1 INVENTOR.

M FORD B. MOORE B. MOORE 3,011,358

GEARHEAD Dec. 5, 1961 Filed Sept. 6, 1960 3 Sheets-Sheet 2 INVENTOR. MILFORD B. MOORE Dec. 5, 1961 Filed Sept. 6, 1960 M. B. MOORE GEARHEAD 3 Sheets-Sheet 3 INVENTOR.

MILFORD B. MOORE United States Patent 3,011,358 GEARHEAD Milford B. Moore, Rochester, N.Y., assignor to Graflex Inc, a corporation of Delaware Filed Sept. 6, 1960, Ser. No. 54,084 2 Claims. (Cl. 74-409) The present invention relates to gear reducers particularly for combination electric motor-gear reduction units, although it can be applied also to other types of geared speed reducers.

One object of the present invention is to provide means for controlling the backlash at the final reduction in a gear reduction unit, namely, the backlash between the driven gear on the output shaft of the unit, and its mating driving pinion. To this end it is a purpose of the invention to provide means for adjusting the center to center distance between the output shaft of the gear reduction unit and the shaft which carries the drive pinion for the output shaft.

Another object of the invention is to provide a better gearhead than heretofore available and having smaller backlash tolerances.

Still another object of the invention is to provide a gearhead which has improved rigidity.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

FIG. 1 is an axial sectional view of a gearhead made according to one embodiment of this invention, and showing the end plate of the unit in one position of adjustment;

FIG. 2 is a top plan view of this unit, partly broken away; 1

FIG. 3 is a bottom plan view of this unit;

FIG. 4 is a developed sectional view of this unit, not a true section, a section taken through the input shaft of the unit and circularly through the other shafts of the unit, and then laid out in a plane; and

FIG. 5 is a similar developed section of a unit made according to another embodiment of this invention.

Referring now to the drawings by numerals of reference, denotes the gearhead as a whole, and 1-1 designates the drive motor for the unit. The gearhead comprises a generally cup-shaped casing 12, which is closed at its lower end by a transversely extending wall or web 14. Adjacent its opposite end the casing 12 is formed with an internally extending annular flange 15 which is spaced axially from the web 14. Mounted upon the flange 15 and secured thereto as by means of dowels 16 (FIG. 4) is a web or plate 17.

The shafts, which carry thegears of the unit, are journaled at their opposite ends in ball bearings 18 and 19, respectively, that are secured in the webs 14 and 17, respectively.

The end of the housing 12, which is remote from the end '14 thereof, the upper end as viewed in FIG. 1, is closed by an end plate 25, which is rotatably adjustable within the cylindrical inside guide surface 26'of the housing formed above the web 15. The end plate seats with its lower face against the upper face of the web or plate 17. The end plate 25 has a bore 27 therethrough which is eccentric of the peripheral surface 28 of the end plate and of the cylindrical guide surface 26 within which the peripheral surface 28 engages.

Journaled on anti-friction bearings 29 and 30 in the bore 27 is the output shaft of the unit. Bearing 29 is spaced from bearing 30 by a spacer 33 and is held in place by snap-rings 31 and 32. The shaft 35 has a gear 36 integral with or secured to it, which is driven from the motor 11 through any desired number of gear reduction pairs. In the illustrated embodiment of the invention, the armature shaft 37 of the motor projects into the housing 12 through'an opening 38 in the web 14 and carries, or has secured to it, at its upper end'a drive pinion 39. This pinion meshes with a gear 40 (FIG. 4) which may form part of a cluster gear that is secured to or integral with a shaft 41. The shaft 41 has a pinion 42 integral with, or secured to, it which meshes with the gear portion 44 of a cluster gear that includes a pinion 45, and that is secured to or integral with the shaft 46. Pinion 45 meshes with the gear portion 47 of a cluster gear whose pinion portion 48 is integral with, or secured to, the gear 47 and is integral with or secured to the shaft 49. Pinion 48 meshes with a gear 50, which is integral with, or is secured to, a pinion 51 and a shaft 52. Pinion 51 meshes with the gear portion 54 of a cluster gear whose pinion portion 55 is integral with, or is secured to, the gear portion 54 and is integral with or secured to the shaft 56. Pinion portion 55 meshes with the gear portion 57 of a cluster gear whose pinion portion 58 is integral with, or secured to, the gear portion 57 and is integral with, or secured to, the shaft 59. Pinion portion 58 meshes with the gear 36 that is secured to the output shaft 35 of the unit. The shafts 41, 46, 49, 52, '56, and 59 are parallel to one another and are journaled at opposite ends in the ball bearings 18 and 19, respectively, and are arranged circularly about and are equidistant radially from the axis 70 (FIGS. 1 and 2) of input shaft 37. This axis coincides with the axis of internal surface 26 and with the axis of the peripheral surface 28 of the end plate.

The end plate 25- has, in the illustrated embodiment of the invention, four bolt holes 60 through it which are spaced from "one another and which are concentrically arranged about the axis 70. The web '17, flange 15, and the web 14 of the housing 12 have six bolt holes each through them which are equi-angularly spaced and arranged on a bolt circle also concentric with axis 70 and coaxial with the periphery 28 of the end plate and with the inside guide wall 26 of the housing. These bolt holes are designated 61, 62 and 63,'resp'ectively. 7

Four mounting screws or bolts 65 are used to fasten the end plate 25 in the selected angular adjusted position in the housing. The four bolt holes 60' are lined up with a selected four of the six bolt holes in the web 17, flange 15, and web 14; and then the bolts 62 are passed through the aligned bolt holes 60', 61, 62 and 63 to secure the end plate 25 in any angularly adjusted position on thehousing. Thus, the end plate} 25 can have six finite angular positions with respect to the housing. Thus, the distance between the axis 71 of the output shaft 35 and any one of the six shafts 41, 46, 49, 52, 56 and 59, can be varied six times as the end plate is rotatably adjusted through the six possible positionsof its connection to the housing. v

With this construction it is possible to adjust the end plate 25 so as to take up or control the backlash' betwee n the gear 36 on the output shaft 35 and the pinion 58, which meshes therewith, since the rotary adjustment of the end plate provides a means by which the center tov center distance between the output shaft and its driving pinion can be adjusted. Furthermore, this construction permits any number of gear reductions, or meshes,,to be interposed in the housing 12 between the drive or input. shaft 37 and the output shaft 35, up to the number of reductions illustrated in FIG. 4. Thus, pinion 39 on armature shaft 37 of the motor 11 might drive directly a gear on the shaft 59, which carries the pinion 58 meshing with the driving gear 36. A further reduction can be obtained by having the gear 39 mesh with a gear on the shaft 56,

and having a reduction such as shown at 55, 57, 58 to gear 36. Still another arrangement would be to have the gear 39 mesh with a gear such as the gear 50, and retain the reduction 51, 54, 55, 57, and 58 to gear 36. Other arrangements would involve a drive from the shaft 37 to the shaft 49 and thence through the required number of reductions to the gear 36, or from the shaft 37 to the shaft 46, and thence through the required reductions to the shaft 35. Thus, a very great flexibility can be had as to the extent of reduction achieved by the unit between the input shaft 37 and the output shaft 35.

The holes 64 in the end plate 25 are for securing the gear reduction unit to the apparatus which is to be driven by output shaft 35.

The structure of the present invention described gives rigidity. The conventional design is a plate and post construction in which there are two parallel plates which are separated by four posts and there is a slip-on cover. This cover imparts nothing as regards rigidity. in the new design of the present invention the end plate 25 has guidance on the inside wall 26 of the housing 12, and therefore the output shaft 35 is rigidly mounted with reference to the other shafts of the reduction unit. The new design of the present invention, therefore, gives improved rigidity.

The embodiment of the invention shown in FIG. is similar to that already described. For ready comparison of the two embodiments, similar parts in FIG. 5 are denoted by the same numerals as in FIGS. 1 to 4 increased by a hundred. Thus, the end plate in FIG. 5 is denoted at 125 instead of 25, and similarly the output shaft is denoted at 135 in FIG. 5, etc.

The embodiment of FIG. 5 differs from that shown in FIGS. 1 to 4 among other things in that the lower end of the housing 112 is open, and is closed by a web or plate 117 which is doweled to the housing. Plate 117 in other words is secured to the lower end of the housing instead of resting on'the web 115 adjacent the upper end of the housing. The end plate 125 seats directly on this part 115 which is here a web rather than merely a flange.

The embodiment of FIG. 5 further differs from the previously described embodiment in that the shafts 159, 156, 152, etc. of the reduction unit are journaled at opposite ends on bearings 118 and 119 in webs 117 and 115. Only four shafts have been shown in the unit of 1G. 5, but obviously the number of these shafts may be increased or decreased as stated in connection with the previously described embodiment of the invention.

In the embodiment of the invention shown in FIG. 5 moreover, there is an adapter 80 secured to the web 117, end plate 125 and housing 112 by the bolts 165. This adapter has a recess 81 in its lower face to receive one end of the drive motor of the gear reduction unit. The armature shaft (not shown) of this motor projects into the housing 112 through the hole 138 in the adapter 80, and, as before, carries a pinion which drives the train of gearing of the reduction unit. The adapter 80 is centered on the housing by a sleeve 83 that is formed integral with the adapter and that fits into hole 138.

As in the first described embodiment of the invention, the output shaft 135 is mounted in end plate 125 with its axis eccentric of the peripheral surface 128 of the end plate and of the internal surface 126 of the housing in which the end plate fits. Thus upon rotary adjustment of the end plate in the housing, backlash between the final drive pinion 158 of the reduction unit and the gear 136 carried by the output shaft can be taken up to a desired degree; Similar to the first-described embodiment, there may be four equi-angularly spaced bolt holes in the end plate 125 and six bolt holes in the web 115, web 117, and adapter 80, and the end plate 125 is adjusted angularly to line up its four bolt holes with any four of the six in the housing, web 117 and adapter, the four of the six which are selected depending upon the radial distance between axes 70 and 71 (FIGS. 1 and 2) required to provide the desired backlash between gear 136 and drive pinion 15S.

Obviously, of course, the invention is not restricted to use of four bolt holes in the end plate 25 or and six in the housing 12 or 112, but any practical number may be employed in each.

After adjustment, the end plate is secured in adjusted position by passing bolts through the aligned holes and threading them into adapter 80.

While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A gearhead comprising a housing, an input shaft extending into said housing through one end wall thereof, a single cylindrical gear secured to said input shaft within said housing to rotate with said input shaft, an end plate mounted in the opposite end of said housing to close said opposite end of said housing, a web fixedly secured in said housing between said end Wall and said end plate and extending parallel to said end wall, a plurality of shafts journaled at opposite ends, respectively, in said end wall and in said web and arranged in a circle about a common axis, said housing having a peripheralwall whose inside surface, at least beyond said web, is cylindrical and coaxial with said common axis, an output shaft journaled in said end plate eccentrically of said common axis and having one end projecting into said housing and its opposite end projecting outwardly beyond said end plate, said end plate having a peripheral cylindrical surface engaging said inside surface and coaxial therewith, gearing connecting said single gear with one of said plurality of shafts, gearing drivingly connecting said one shaft with another of said plurality of shafts to drive the other shaft from said one shaft, and gearing, including a pair of cylindrical gears, one of which is securedto that end of said output shaft which projects into said housing, for connecting said other shaft with said output shaft, whereby said output shaft is driven from said input shaft, said end plate being rotatably adjustable in said housing about the axis of its peripheral cylindrical surface, thereby to adjust the backlash between said pair of cylindrical gears, and means for securing said end plate in any adjusted position.

2. A gearhead as claimed in claim 1 wherein said securing means comprises a plurality of registering bolt holes in said housing arranged concentrically with said common axis, a plurality of bolt holes in said end plate in equi-angular spaced relation about an axis, the number of bolt holes in said end plates being less than in said housing and a plurality of bolts remova'bly secured in said bolt holes to fasten said end plate in any adjusted position.

References Qited in the file of this patent UNITED STATES PATENTS 2,507,555 

